Inaug.-diss.--Leipzig. / Vita. Includes bibliographical references.

Inaugural-Diss.--Mathematisc-Naturwissenschaftlichen Fakultät--Bonn--Rheinischen Friedrich-Wilhelms-Universität, 1992. / Bibliogr. p. 142-154.

Th.--Sci. nat.--Nancy 1, 1982. N°: 758.

Th.--Sci.-nat.--Nancy, 1982. / Bibliogr. p. 233-250. Résumé en français et en anglais.

Th.--Géol.--Toulouse 3, 1977. N°: 779.

Granulites are the dense, strong metamorphic rocks that are produced during high- (HT) to ultrahigh-temperature metamorphism (UHT) and partial melting of Earth's crust. Granulites are ubiquitous in exhumed Archean cratons and are thought to comprise much of Earth's stable lower crust. Understanding the mechanisms responsible for crustal heating in Archean terranes is thus paramount to understanding the stabilisation of early continental crust, and whether such mechanisms resemble modern tectonic processes. It is therefore important to quantify the pressure–temperature–time (P–T–t) paths of Archean granulites, as such paths can be diagnostic of heating mechanism. This dissertation explores: 1) novel approaches to reconstructing the P–T–t paths of granulites, and 2) what the deciphered P–T–t paths of rocks from two Archean granulite terranes reveal about Archean crustal heating. The first chapter shows how petrologic modelling at multiple scales from a texturally heterogeneous granulite can provide "snapshots" of the P–T path, which would be difficult to reconstruct otherwise. The remaining chapters are focused on reconstructing the P–T–t paths of two Archean granulite terranes: the Beartooth Mountains, and the Pikwitonei granulite domain (PGD). The second and third chapters present evidence for cryptic HT metamorphism of the Beartooth granulites at ~2.7 Ga characterized by rapid (< 1 Ma) exhumation at HT and fast cooling (~10-100 C/Ma) in the middle crust. This suggests advective/conductive heating over short length-scales. In the fourth chapter, thermobarometric data suggest the western PGD experienced UHT decompression followed by cooling in the lower crust. High-precision zircon and monazite dates reveal apparently episodic crystallization over at least ~24 Ma. This episodicity could reflect multiple thermal cycles or the control of local reactions on zircon/monazite crystallization during cooling. High-spatial resolution petrochronology provides temporal constraints on prograde metamorphism. These data suggest metamorphism in the PGD was driven by a long-lived heat source over large length-scales near the base of the lithosphere. Disparities in the timescales, length-scales, and the depth and amount of heating between the terranes may suggest different crustal heating mechanisms in each, and that the late Archean Earth may have been tectonically diverse. / Ph. D. / Granulites are the dense and strong rocks that are produced during extreme heating, high- (HT) to ultrahigh-temperature (UHT) metamorphism, and partial melting of Earth’s continental crust. Granulites are common in exhumed fragments of Earth’s ancient, Archean (> 2.5 billion yrs old) crust and are thought to comprise much of Earth’s stable lower crust. Understanding the mechanisms responsible for extreme heating of the crust is thus crucial to understanding how Earth’s early continents were stabilised, and how plate tectonic processes have evolved through Earth history. Metamorphic rocks preserve a commonly cryptic record of the path(s) they took through the crust, which are controlled in part by the heating mechanism(s) and tectonic settings involved in their genesis. It is therefore important to quantify the pressure–temperature–time (<i>P– T–t</i>) paths of Archean granulites, as such paths may be diagnostic of particular crustal heating mechanisms. This dissertation explores: 1) novel approaches to reconstructing the pressure– temperature–time (<i>P–T–t</i>) paths of granulites, and 2) what the deciphered <i>P–T–t</i> paths of rocks from two Archean granulite terranes reveal about Archean crustal heating. The first chapter presents a novel way to reconstruct the <i>P–T</i> path of a texturally complex and heterogeneous rock, which reveals a more detailed history than conventional methods would. The second, third, and fourth chapters are focused on reconstructing the <i>P–T–t</i> paths of granulites from two Archean terranes that record HT/UHT metamorphism ~2.7 billion years ago: the Beartooth Mountains, and the Pikwitonei granulite domain (PGD). These studies show that crustal heating of the Beartooth granulites was brief (< 1 million years duration) and seems to have occurred over short length-scales in the middle crust, while crustal heating of the PGD was long-lived (> 24 million years duration) and occurred over large length-scales near the base of the crust. The disparities in the timescales, length-scales, and the depth and amount of heating between the two terranes may suggest different crustal heating mechanisms operated in each, and that the Earth may have been tectonically diverse ~2.7 billion years ago.

Thesis (M.S.)--University of Wisconsin--Madison, 1984. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 165-173).

Th.--Sci. nat. Nantes, 1977.

This diploma thesis deals with the oldest recognized deformation microstructure of felsic granulites of Blanský les (southern Bohemian Massif) in order to understand their lower crustal deformation history later altered during exhumation. Moreover, the study is focused on decomposition of ternary feldspars in the proto-phase of evolution of granulite microstructure. Based on the structural and microstructural analyses of the less developed cleavage I. and the more developed cleavage II., it was possible to distinguish between two deformation structures. The S1 is defined by compositional banding of alternating quartz bands with bands rich in plagioclase, garnets and with porphyroclasts of alkaline feldspars. The S1 cleavage is transposed into the S2 cleavage. During intense reworking of S1 into S2, the quartz bands were decomposed and recrystallized into the ribbons. The feldspar thermometry of the cleavage I. and II. allowed to distinguish the three stages of decomposition of feldspars. A continuous temperature decrease was observed as reflected by the individual microstructures. The quantitative microstructural analysis indicate the shape preferred orientation of the grain boundaries of two-feldspar matrix. The shape preferred orientation of cleavage I. is controlled by the albite rim, however after its...

Bibliography: leaves 181-196. / 196, 44a leaves : ill. (some col.), maps ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Geology and Geophysics, 1994